1. Field of the Invention
The invention relates to electronic circuits, particularly to electronic oscillator circuits.
2. Description of the Background Art
Oscillator circuits are used in electronic system and circuit designs for generating clock signals or other periodic signals which vary current or voltage of a generated signal sinusoidally or alternately between maximum and minimum levels. Oscillator circuits are also used for generating periodic signals having a phase which is specified relative to other periodic signals.
A common technique for generating oscillating signals using metal-oxide-semiconductor (MOS) technology is by coupling an odd set of inverting MOS circuits or stages serially in a ring, such that a signal or pulse may be propagated cyclically within the stages in the ring. In this ring arrangement, the oscillating signal may be obtained from one of the stage outputs, while the pulse is cycled therein.
Such known ring oscillators, however, generate typically only an odd number of signal phases. Thus, it would be desirable to provide an improved MOS-type ring oscillator which generates any number of signal phases.